Proteinuria, also known as albuminuria or urine albumin, is too much protein in the urine. The kidneys normally excrete under 150 milligrams of protein in the urine in a day. When the amount is higher, something is wrong with the kidneys.
In its early stages, proteinuria has no symptoms. As the condition progresses and more protein is lost, urine may look foamy. Swelling (edema) may occur in the face, hands, feet and abdomen.
There are three types of proteinuria: transient (comes and goes), orthostatic (affected by one's position) and persistent (constant).
Transient proteinuria, the most common type, is caused by temporary factors like fever or exercise. No treatment is usually required.
Orthostatic proteinuria is rare past the age of 30 but affects 2 to 5 percent of teenagers. The amount of protein being excreted is abnormally high while sitting or standing, but is normal while lying down. Its cause is unknown.
Fortunately, this form is not dangerous, and tends to disappear as the individual gets older. No treatment is necessary.
Persistent proteinuria is a symptom of diseases such as diabetes, cardiovascular disease or hypertension (high blood pressure). Treating the disease, for instance, lowering blood pressure in hypertension, or blood sugar in diabetes, will relieve proteinuria.
Overweight and advanced age also increase the likelihood of developing the persistent form.
The presence of proteinuria can be detected by urinalysis (testing the urine). Testing is commonly done more than once to note any changes in the amount of protein in the urine.
A 24-hour urine collection is sometimes taken. The individual urinates into a container, starting first thing in the morning. The container is refrigerated between bathroom breaks. Urine is collected throughout the day, and also from the first trip to the bathroom upon getting up the next morning.
Dipstick tests can determine whether or not excess protein is present. If so, further testing is called for.
The next step is microscopic urinalysis. This determines the contents of the urine, by use of a microscope. If protein is found after testing, the doctor will want to perform a medical history and physical exam.
A blood test may be recommended if more information is needed.
If still more data is required, a nephrologist (specialist in kidney diseases and transplantation, and kidney dialysis therapy) may do more blood and urine tests, and a kidney ultrasound.
Where indicated, a renal (kidney) biopsy can help to diagnose any kidney disease present.
Sources
Merck: Proteinuria
http://www.merck.com/mmpe/sec17/ch226/ch226k.html
Proteinuria
http://emedicine.medscape.com/article/238158-overview
Proteinuria
http://kidney.niddk.nih.gov/kudiseases/pubs/proteinuria
Kidney Restore: Proteinuria
http://www.kidney-restore.com/ailments/proteinuria.html
Patient information: Protein in the urine (proteinuria)
http://uptodateonline.com/patients/content/topic.do?topicKey=~LxxrP_d.kF.dlL&source=see_link
Orthostatic or postural proteinuria
http://www.utdol.com/patients/content/topic.do?topicKey=~8xGGpYRK1TN4/x
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